System of manufacturing a surgical kit for cartilage repair in a joint

ABSTRACT

A manufacturing system for a surgical kit includes surgical tools and an implant for cartilage repair in an articulating surface of a joint. The design system includes the basic blocks of: I. Receiving design parameters for a surgical kit in a computer controlled manufacturing system, the design parameters for the surgical kit representing a model for a medical implant and a guide tool for implanting the implant; II. Manufacturing a medical implant dependent on the design parameters; and III. Manufacturing a guide tool for implanting the implant dependent on design parameters.

FIELD OF THE INVENTION

This invention relates in general to the field of manufacturing asurgical kit with tools and an implant for replacement of damagecartilage in an articulating surface in a joint.

BACKGROUND

1. General Background

Pain and overuse disorders of the joints in the body is a commonproblem. The weight-bearing and articulating surfaces of the knees, andof other joints, are covered with a layer of soft tissue that typicallycomprises a significant amount of hyaline cartilage. The frictionbetween the cartilage and the surrounding parts of the joint is verylow, which facilitates movement of the joints under high pressure. Thecartilage is however prone to damage due to disease, injury or chronicwear. Moreover it does not readily heal after damages, as opposed toother connective tissue, and if healed the durable hyaline cartilage isoften replaced by less durable fibrocartilage. This means that damagesof the cartilage gradually become worse. Along with injury/disease comesa problem with pain which results in handicap and loss of function. Itis therefore important to have efficient means and methods for repairingdamaged cartilage in knee joints.

The advantages of implants have stimulated a further development ofsmaller implants that can be implanted with less invasive surgery. Inthis development there has also been an effort to achieve small jointimplants, suitable for repair of a small cartilage injury that have aminimal influence on the surrounding parts of the joint. In the surgicaloperation of implanting such small implants it is critical that theimplant is positioned in a precise manner. If the implant is offset fromits intended position it may cause an increased wear or load on thejoint. For example, if the implant is tilted this may result in an edgethat projects above the cartilage surface and causes wear on theopposing cartilage in the joint. Another example is the case that theimplant is placed in a too shallow position, which may result in a toohigh top of the implant that causes the joint to articulate in an unevenmanner and increase the load on an opposing point of the joint. For thepatient, also small misplacements or deviations from an ideal positionmay result in pain, longer time for convalescence or even a surgicaloperation being done in vain and making it more difficult to repair thedamage in the joint. A large burden is therefore placed on the surgeonnot to misplace or misfit the implant. There is therefore a need forwell fitting implants as well as tools that are designed to relieve andsupport the surgeon in the implant surgery.

The design of the implant and the surgical tools, in other words, thedesign of the surgical kit is crucial for the outcome of the implantslife-time in a joint. Also, the parameters for designing are ofuttermost importance for the result in these operations. Smalldifferences in the design can make a huge difference in fit andlife-time of an implant in the body, convalescence time for the patient,economic values due o surgery time, success of operations, also thenumber of successful operations will increase and the working conditionsfor the surgeon will be improved if the designing parameters areselected right.

2. Specific Background

Another important factor for achieving high quality implants andefficient implantation is the manufacturing system. Various methods ofmanufacturing patient specific implants are known.

PRIOR ART

Prior art document which describe the manufacturing of orthopedicimplants is for example:

US2008/0257363 A1 shows an orthopedic implant manufacturing method.

US2003/0216669 A1 shows methods and compositions for producing articularrepair materials for repairing an articular surface.

WO2007/092841 A2 shows methods, compositions and tools for repairing anarticulate surface.

WO2006060416 A2 shows implants with a complex clinically acceptableproximal surface.

OBJECT OF THE INVENTION

The general object of the invention is to solve the problem ofmanufacturing an improved surgical kit for replacing damaged cartilage.

SUMMARY OF THE INVENTION

The object of the invention is achieved with a system for manufacturinga surgical kit comprising surgical tools and an implant for cartilagerepair in an articulating surface of a joint. The manufacturing is basedon design parameters that have been generated in a computer aided designsystem based on image data of the joint. The design parameters are inputto and received by the computer controlled manufacturing system,manufacturing control parameters for controlling manufacturing machinesare generated, and the manufacturing machines are controlled to producean implant and associated surgical tools dependent on the designparameters.

The manufacturing system comprises the basic blocks of:

I. Receiving design parameters for a surgical kit in a computercontrolled manufacturing system, said design parameters for the surgicalkit representing a model for a medical implant and a guide tool forimplanting said implant.

II. Manufacturing a medical implant (10) dependent on the designparameters.

III. Manufacturing a guide tool (12) for implanting said implant (10)dependent on design parameters.

BRIEF DESCRIPTION OF THE FIGURES

The invention will be further explained with reference to theaccompanying drawings, in which:

FIG. 1 schematically illustrates the design process according to anembodiment of the inventive concept for designing a surgical kit.

FIG. 2 shows a surgical kit according to one embodiment of theinvention, exemplified by a surgical kit for a knee, the surgical kitcomprising an implant and a set of tools.

FIG. 3 a-b shows an exemplifying embodiment of an implant according tothe present invention.

FIG. 4 a-b shows an exemplifying embodiment of a guide tool according tothe present invention.

FIG. 5 a-b shows an exemplifying embodiment of a cutting tool accordingto the present invention, a punch.

FIG. 6 a-b shows an exemplifying embodiment of a drill guide accordingto the present invention.

FIG. 7 a-f shows an exemplifying embodiment of a drill, reamer bit,reamer guide and hammer tool according to the present invention.

FIG. 8 a-b shows an exemplifying embodiment of the cross-sectionalprofiles of the implant and the tools of the surgical kit.

FIG. 9 a-f shows an exemplifying embodiment of the surgical method usingthe surgical kit according to the invention.

FIG. 10 shows an exemplifying embodiment of a cutting tool according tothe present invention, a cutting drill

FIG. 11 shows an image of a guide tool designed according to anembodiment of the design method. In this exemplifying embodiment of theguide tool, the guide body comprises an orifice at the foot of the guidebody that leads from the guide channel into the open outside the guidebody.

FIG. 12 a-b shows an exemplifying embodiment of cartilage damage in thetibia bone. The figure represents a sample image, in a side view, from aset of several images which together represents a three dimensionalimage of a joint.

FIG. 13 shows schematically in an exemplifying embodiment of theinvention how image based tools of the invention may be used tovisualize, in an image, a model of a recess in the cartilage and thesubchondral bone for an implant.

FIG. 14 shows schematically in an exemplifying embodiment of theinvention how image based tools of the invention may be used tovisualize in, an image, a model of an inserted implant according to thegenerated design parameters.

FIG. 15 a-b shows an example of a front view of the articular cartilageof the femur bone.

FIG. 16 schematically illustrates the manufacturing process according toan embodiment of the inventive concept.

FIG. 17 shows an exemplifying embodiment of a drill depth adjustmenttool placed on a guide tool together with a drill bit and a depth gaugeand a drill guide according to the present invention

FIG. 18 shows an exemplifying embodiment of more details of the drilldepth adjustment tool according to the present invention

FIG. 19A-B shows an exemplifying embodiment of how the drill depthadjustment tool may be used together with the drill guide and the guidetool.

DETAILED DESCRIPTION OF THE INVENTION

Manufacturing System

The present invention is directed to a system, comprising a method,apparatus and computer programs, for manufacturing, dependent onpredetermined design parameters, a surgical kit comprising a medicalimplant and associated tools for use in a surgical implant operation.The associated set of tools is devised for the placement of an implantthat replaces damaged cartilage in a joint and is adapted to thespecific implant as well as a specific joint for which the implant isintended. The surgical kit provided by the present invention has theeffect that successful implant insertion is less dependent on surgicalcircumstances and the skills of the surgeon compared to previously knownimplants. Due to the design, the manufacturing and the function of bothtools and implant the surgical kit gives improved implantation precisionand a precise desired placement of the implant in the joint every time.The precision of the surgery is “built in” into the design of the tools.

FIG. 2 shows an example of a surgical kit designed according to a methodof one embodiment of the present invention. This particular exemplifyingembodiment of a surgical kit according to the invention is especiallyadapted for cartilage replacement at the femur of a knee joint. Theinvention may however be applied for cartilage replacement in anarticulating surface in any other joint in the body, e.g. elbow, ankle,finger, hip, toe and shoulder. The shown surgical kit, thus being shownin an adaptation for a knee joint comprises an implant 10 with anextending post 23 and implant associated tools; a guide-tool 12 equippedwith a guide-channel 13, a positioning body n and a drill guide 8.Further the surgical kit may comprise a cutting tool 6, which in thisexemplifying embodiment is a punch, a drill-bit 8, preferably equippedwith a depth gauge 1 and/or a reamer-bit 4, preferably equipped with adepth gauge 3, and/or a hammer tool 35 and/or a reamer guide 28. Thedetails of the surgical kit are described further below.

FIG. 1 schematically illustrates the design process according to anembodiment of the inventive concept for designing a surgical kit. Thedesign system comprises the basic blocks of:

I. Determining physical parameters for a cartilage damage in a joint.

II. Generating design parameters of a medical implant 10.

III. Generating design parameters of a guide tool 12 for implanting theimplant.

The physical parameters as well as the design parameters are representedas digital data that is processed or generated by specifically designedcomputer program code portions executed in a data processing system. Thesystem may be fully automated or may comprise portions of computersupported manual steps of for example selections. The design parametersresulting from the process are stored in a format suitable for use asinput in an automated manufacturing process.

FIG. 16 schematically illustrates the manufacturing process according toan embodiment of the inventive concept. The manufacturing systemcomprises the basic blocks of:

I. Receiving design parameters for a surgical kit in an automated, atleast partly computer controlled, manufacturing system, said designparameters for the surgical kit representing a model for a medicalimplant and a guide tool for implanting said implant.

II. Manufacturing a medical implant 10 dependent on the designparameters.

III. Manufacturing a guide tool 12 for implanting said implant 10dependent on design parameters.

The manufacturing of the implant and the different parts of the surgicaltool is for example conducted by a computer controlled machines forlaser sintering (additive manufacturing), turning, milling or reaming.Suitable material and possible workpieces are selected for the differentcomponents.

Design Parameters for the Implant and the Guide Tools

I. Determining Physical Parameters for a Cartilage Damage in a Joint.

An image or a plurality of images 91 representing a three dimensionalimage of a bone member of the joint 90 in a patient's limb 92 isobtained by a selected one of a per se known imaging technology fornon-invasive imaging of joints, such as magnetic resonance imaging(MRI), computerized tomography (CT) imaging or a combination of both, orother suitable techniques such as delayed Gadolinium-enhanced MRI ofcartilage (dGEMRIC) techniques. The image of the joint should comprise arepresentation of cartilage in the joint as well as the underlyingsubchondral bone in the area of the cartilage damage. Image data makingup a three dimensional image representation of the joint is stored in adigital format in a manner that enables to keep track of the dimensionsof the real joint that the image depicts.

The image data 94 is analyzed in a data processing system 93 to identifyand determine physical parameters for the cartilage damage. The physicalparameters to determine comprise the presence, the location and the sizeand shape of the cartilage damage, as well as curvature of the surfacecontour of the cartilage or the subchondral bone in an area of thecartilage damage.

In one embodiment of the inventive concept the design system operates todetermine physical parameters on images of the patient's individualjoint and the current cartilage damage, and thereby produces anindividually designed surgical kit. In another embodiment the designsystem operates on a collection of images of joints constituting astatistical basis for determining physical parameters for producing asurgical kit adapted for a selected location and a selected size ofcartilage damage in a joint of a selected size.

The following steps are in one embodiment comprised in determining thephysical parameters:

-   a. Obtaining image data representing a three dimensional image of a    bone member of the joint.    -   By way of example, FIG. 12 illustrates schematically a sample of        a set of several images which together represents a three        dimensional image of a joint. FIG. 12A shows a cross-section of        a knee joint 133 with a femur bone 131, a patella bone 134, a        tibia bone 137 and a fibula bone 138. Articular cartilage 132        and 136 is found on the femur and the tibia bone, respectively.        FIG. 15 a-b shows a front view of the articular cartilage parts        130 of the femur bone.-   b. Identifying in the image data cartilage damage in an articulate    surface of the bone member.    -   In an automated process a computer program would be adapted to        scan the image data for predetermined characteristics of a spot        of cartilage damage in the image data. In a process with a        manual part in this step an operator would visually scan a        displayed image of the joint and identify a spot that has the        visual characteristics of cartilage damage. FIG. 12A shows an        example of cartilage damage 139 in the tibia bone and FIG. 15A        shows an example of cartilage damage 139 in the femur bone in a        front view.-   c. Determining based on the image data the location of the cartilage    damage.    -   A set of data that represents a position of the cartilage damage        in the joint is selected automatically or manually. The position        data is for example stored as a set of defined coordinates in        the image data.-   d. Determining based on the image data the size and shape of the    cartilage damage.    -   Selected measurements for size and shape of the cartilage are        calculated in the image date, for example by determining a        boundary line for the healthy cartilage surrounding the        cartilage damage. FIG. 15B illustrates as an example of how a        predetermined or selected circular cross-section shape 140        having a two-dimensional extension is automatically or partly        manually matched over the cartilage damage. A circular        cross-section shape 140 is preferably selected such that it        covers the cartilage damage with a perimeter at a predetermined        safe distance from the fringes of the damaged cartilage. FIG.        12B illustrates an example of that the thickness 144 of healthy        cartilage is determined around the perimeter of the        cross-section shape 140 extending over the damaged cartilage.        The size and shape data is for example stored as a set of        perimeter and thickness data with a predetermined resolution.-   e. Determining based on the image data the surface contour curvature    of the cartilage and/or the subchondral bone in the joint in a    predetermined area comprising and surrounding the site of cartilage    damage.    -   The curvature of the surface contour is determined for example        by per se known surface matching methods in image processing.        The determined curvature information can be represented as an        equation or as a set of image data. The determined curvature        preferably comprises two subsets of curvature information.        Firstly, one subset comprises the curvature of the contour        portion that comprises the cartilage damage within the        cross-section shape 140 defining the selected boundary line for        the area covering the cartilage damage. Secondly, the second        subset comprises the curvature of a contour portion that        surrounds the site of cartilage damage, preferably comprising        mutually opposing sloping parts.

II. Generating Design Parameters for a Medical Implant (10).

Based on the physical parameters for the cartilage damage, designparameters for an implant are generated by processing the physicalparameters in a design stage 95 according to a predetermined scheme forthe shape of an implant in the specific surgical application.

The shape and size of the implant are calculated or selected dependenton the size and shape of the cartilage damage, and dependent on thecurvature of the contour of the cartilage and/or of the subchondral bonein the area substantially coinciding with the cartilage damage.

The following steps are in one embodiment comprised in generating designparameters for a medical implant:

-   f. Generating the contour curvature for an articulate surface of a    substantially plate shaped implant body 27 dependent on said    determined surface curvature of the cartilage and/or the subchondral    bone.    -   The contour curvature for the articulate surface of the implant        body is generated to correspond to the curvature that covers the        cartilage damage.-   g. Generating a cross-section for the implant body dependent on and    substantially corresponding to said determined size and shape of the    damaged cartilage.    -   The cross-section for the implant body is generated to        correspond to the cross-section shape 140 determined for the        cartilage damage.-   h. Generating an edge height 14 for the implant body that    substantially corresponds to the thickness of healthy cartilage plus    a selected height of a bone contacting part of the implant for    countersinking the implant into a recess to be made in the bone to    fit and receive the implant.    -   A first part of the edge height 14 for the implant body 27 is        generated to correspond to the determined height 144 of the        healthy cartilage, and a second part corresponds to a        countersink height selected automatically according to a        predetermined scheme or selected manually by an operator.-   i. Generating a length and a cross-section profile for an extending    post 23 extending from a bone contacting surface of the implant    dependent on predetermined rules related to the size and shape of    the cartilage damage.    -   The size and shape of the extending post is selected        automatically according to a predetermined scheme or is selected        manually by an operator.    -   FIG. 13 shows schematically how image based tools of the        invention may be used to visualize in an image a model of a        recess 135 in the cartilage and the subchondral bone for an        implant and FIG. 14 shows an inserted implant 10 according to        the generated design parameters. The image based tool may also        be configured for using predetermined shapes that are adapted to        the determined physical parameters to automatically or manually        fit to the cartilage damage and thereby generate the design        parameters.

III. Generating Design Parameters for a Guide Tool 12 for Implanting theImplant.

The design parameters for the guide are generated dependent on thephysical parameters for the cartilage damage and dependent on the designparameters for the medical implant.

The following steps are in one embodiment comprised in generating designparameters for a guide tool:

-   j. Generating contact points for a cartilage contact surface 50 of a    positioning body 11 dependent on said determined surface contour    curvature of the cartilage and/or the subchondral bone in the joint    in a predetermined area comprising and surrounding the site of    cartilage damage, such that said cartilage contact surface 50 of the    positioning body fits to said surface contour of the cartilage or    the subchondral bone in the joint.-   k. Generating the cross-section profile for a guide channel 54 in a    guide body 13 extending from the positioning body, said guide    channel 54 passing through said positioning body 12 and said guide    body 13,    -   the cross-section profile for the guide channel being generated        dependent on and substantially corresponding to said determined        size and shape of the damaged cartilage, and such that the guide        channel 54 is designed to have a cross-sectional profile 82, 122        that corresponds to the cross-section 81 of the plate shaped        implant body 27, and such that the guide channel 54 is designed        to have a muzzle 29 on the cartilage contact surface 50 of the        positioning body at a position corresponding to the site of the        diseased cartilage.-   l. Generating the cross-section profile for an insert tool to have a    cross-sectional profile that corresponds to the cross-sectional    profile 82, 122 of the guide channel 54 with a tolerance enabling    the insert tool to slide within the guide channel 54. The insert    tools are in different embodiments of the invention provided in the    form of a cartilage cutting tool, a punch, a cartilage cut drill, a    drill guide, a reamer guide and/or a hammer tool and/or a drill    depth adjustment tool 2000.

Further Embodiments

Embodiments of the invention further comprise optional combinations ofthe following:

-   m. Generating the cross-section profile for a drill guide 8 to have    a cross-sectional profile (84, 124) that corresponds to the    cross-sectional profile 82, 122 of the guide channel 54 with a    tolerance enabling the drill guide 8 to slide within the guide    channel 54, and generating position and dimension parameters for a    drill channel 7 through the drill guide for guiding a drill bit 1,    the drill channel 7 being placed in a position that corresponds to    the position of the extending post 23 of the medical implant 10.-   n. Generating design parameters for a drill bit 2 dependent on the    design parameters for the extending post and such that a    cross-sectional area for a drill bit is slightly smaller than the    cross-sectional area for the extending post 23.-   o. Generating design parameters for the drill channel 7 comprises    generating a cross-sectional area that matches the cross-sectional    area of the drill bit 2 with a tolerance enabling the drill bit 2 to    slide within the drill channel 7.-   p. Generating design parameters for the drill bit comprises    generating dimensions and position for a depth gauge 1 on the drill    bit for adjustment of the depth of drilling.-   q. Generating design parameters for a reamer guide 28 with a    cross-sectional profile that is slightly smaller than the    cross-sectional profile 82 of the guide channel 54 with a tolerance    enabling the reamer guide 28 to slide within the guide channel 54.-   r. Generating design parameters for a cartilage cutting tool 6, 105    with a cross-sectional profile (83, 123) that is designed to    correspond to the cross-sectional profile 82 of the guide channel 54    with a tolerance enabling the cartilage cutting tool 6, 105 to slide    within the guide channel 54.-   s. Generating design parameters for a cartilage cutting tool 6, 105    comprises generating design parameters for a cutting tool in the    form of a punch 6 having an end with a cutting surface 60, said end    having a recess 5 with a cross-sectional profile 83 that    substantially corresponds to the cross-section 81 of the plate    shaped implant body 27.-   t. Generating design parameters for a cartilage cutting tool 6, 105    comprises generating design parameters for a cutting tool in the    form of a cartilage cut drill 105 having a cross-sectional profile    that substantially corresponds to the cross-section 81 of the plate    shaped implant body 27.-   u. Generating design parameters for the implant comprises generating    design parameters for an implant body 27 of the implant 10 being    substantially flat, having a thickness 14 of approximately 0.5-5 mm.-   v. Generating design parameters for the positioning body comprises    generating design parameters for the cartilage contact surface of    the positioning body having three contacting points 40, 42, 44,    spread out around the guide body 13, for contacting parts of the    joint in order to provide stable positioning of the guide tool 12 in    the joint.-   w. Generating design parameters for the guide channel 54 to have a    height 31 of 3-10 cm.-   x. Generating design parameters for the guide channel comprises    generating design parameters for an orifice leading through the    guide body 13 at the foot of said guide body.-   y. Generating design parameters for a hammer tool 35 with a    cross-sectional profile (86, 126) that is designed to correspond to    the cross-sectional profile 82 of the guide channel 54 with a    tolerance enabling the hammer tool 35 to slide within the guide    channel 54.-   z. Generating design parameters for a depth adjustment tool 2000, se    FIG. 17 and FIG. 18. The depth adjustment tool 2000 according to the    present invention comprises a drill depth bit 2012, a drill depth    assembly holder 2010 and a drill depth spacer 2008. The depth    adjustment tool 2000 is designed to fit onto the top of the guide    channel 54 comprising the drill guide 8 and also designed to be able    to be secured on the guide channel 54.

FIG. 11 shows an image of a guide tool designed according to anembodiment of the design method. The guide tool is positioned on arepresentation of a femoral bone 141 over the site of the cartilagedamage with its positioning body 11 fitted to the contour of the areasurrounding the cartilage damage. A cutting tool 143 such as a bore or areamer is placed in the guide channel of the guide body. The guide body13 comprises an orifice at the foot of the guide body that leads fromthe guide channel into the open outside the guide body. The orifice isdesigned to enable output of waste such as cartilage tissue and bonechips from boring or reaming in the preparation of the recess for theimplant in the joint. The orifice is preferably also designed to enablevisual inspection into the implant site during surgical operation.

Details of the Surgical Kit

The Implant Structure

FIG. 3 a-3 b shows a medical implant 10 of a surgical kit according toan embodiment of the inventive concept. The plate shaped implant body 27has an articulate surface (first surface) 15 configured to face thearticulating part of the joint and a bone contact surface (secondsurface) 21 configured to face bone structure in the joint, the plateshaped implant body 27 has a cross-section (see FIG. 8 a-b implant 10with two different cross-sectional views, 81 and 121) that substantiallycorresponds to the area of the damaged cartilage and the articulatesurface 15 has a curvature that substantially corresponds to thecurvature of a healthy articulating surface at the site of diseasedcartilage. The extending post 23 extends from the bone contact surface21. Since the implant 10 of the inventive concept is custom made for aspecific patient, FIG. 3 a-b is an exemplifying schematic picturedisplaying one embodiments of the implant 10. Between the articulatesurface 15 and the bone contact surface 21 there is a cartilagecontacting surface 19.

The implant is specially designed, depending on the knees appearance andthe shape of the damage and in order to resemble the body's own parts,having a surface which preferably corresponds to a three dimensional(3D) image of a simulated healthy cartilage surface. The implant will betailor-made to fit each patient's damaged part of the joint.

Implant Body

The implant body 27 is substantially plate shaped, meaning that theshortest distance (represented by 24 in FIG. 3) crossing the surface 15of the implant body 27 is substantially larger, e.g. at least 1.5 timeslarger than the thickness 14 of the implant body 27. By substantiallyplate shaped is meant that the implant body 27 may be substantially flator may have some curvature, preferably a 3D curvature of the articulatesurface 15. The articulate surface 15 may for example have a curvaturethat corresponds to a simulated healthy cartilage reconstructed from animage taken e.g. with MRI or CT-scanning of the damaged cartilagesurface of the joint. Once the implant 10 is placed in the joint therewill be a surface with no parts of the implant pointing up from or downbelow the surrounding cartilage—the implant is incorporated to give asmooth surface.

The area and the shape of the implant surface 15 are individualdepending on the size of cartilage damage and location of the cartilagedamage. The area and shape of the implant can be decided by the surgeonhimself or be chosen from predetermined shapes. For instance thecross-section of the implant body 27 may have a circular or roughlycircular, oval, triangular, square or irregular shape, preferably ashape without sharp edges (see FIG. 8 a-b and implant 10). The implanthead or implant body 27 can vary in size and shape and are adjusted tothe size and shape of the damaged cartilage tissue and to the needs ofparticular treatment situations. The size of the implant 10 may alsovary. The area of the articulate surface 15 of the implant varies indifferent realizations of the inventive concept between 0.5 cm² and 20cm², between 0.5 cm² and 15 cm², between 0.5 cm² and 10 cm², between 1cm² and 5 cm² or preferably between about 0.5 cm² and 5 cm².

In general, small implants are preferred since they have a smallerimpact on the joint at the site of incision and are also more easilyimplanted using arthroscopy or smaller open surgical procedures. Theprimary factor for determining the size of the implant is however thenature of the lesion to be repaired.

The extending Post

The implant replaces an area of damaged cartilage in an articulatingsurface of a joint. Before the implant is placed in the desiredposition, the damaged cartilage is removed and also a part of the bonebeneath, i.e. a recess fitting the implant is made in the bone.Furthermore, a hole can be drilled in the bone to fit the implantstructure. The extending post of the implant or the rod-part 23 of theimplant 10, is used for securing the implant 10 in the drilled hole ofthe bone. The length 22 of the extending post 23, extending from theimplant head 27, is adjusted to a length needed to secure the implant 10in the bone. The extending post 23 is intended to give a primaryfixation of the implant 10, it provides mechanical attachment of theimplant 10 to the bone in immediate connection with the surgicaloperation.

The position of the extending post 23 on the bone contact surface 21 canbe anywhere on the bone contact surface 21 or the extending post 23 mayhave a central position.

The extending post 23 has a physical structure in the form of forexample a cylinder or other shapes such as one or more of a small screw,peg, keel, barb or the like.

In one embodiment, the extending post 23 has a positioning part 25,where the positioning part 25 is located distal to the plate shapedimplant body 27. The longitudinal symmetry axis of the first part of theextending post 23 and the positioning part 25 coincide. The diameter ofthe positioning part 25 is smaller than the diameter of the first partof the extending post 23.

The Set of Tools

The set of tools comprises a guide tool with a guide channel and aselection of insert tools for use when mounting the implant on theimplant site. The insert tools are operated inserted in the guidechannel 54 of the guide tool 12 and fits in the guide channel 54, with aslight tolerance to allow a sliding movement of the insert tool in theguide channel 54. The cross-sectional profile, and thus thecircumferential shape of the insert tool, corresponds to the chosencross-section 81 or 121 of the implant surface 15 in size and shape (seeFIG. 8 a-b). The insert tools are in different embodiments of theinvention provided in the form of a cartilage cutting tool, a punch, acartilage cut drill, a drill guide, a reamer guide and/or a hammer tool.The insert tools are used together with further tools such as a drillbit and/or a reamer bit and/or a drill depth adjustment tool 2000.

The Guide-Tool

FIGS. 2 and 4 a-b shows exemplifying embodiments of a guide-tool 12. Theguide tool 12 comprises a positioning body 11 and a guide body 13, witha guide channel 54 through said guide body 13 and positioning body 11.The positioning body has a cartilage contact surface 50 that has a shapeand contour that is designed to correspond to and to fit the contour ofthe cartilage or the subchondral bone in the joint in a predeterminedarea surrounding the site of diseased cartilage. The guide tool 12 alsohas a top surface 52 facing the opposite direction compared to thecartilage contacting surface 50. The guide body 13 extends from said topsurface 52 of the guide tool 12.

The guide channel 54 has an inner cross-sectional profile 82 or 122 (seeFIG. 8 a-b) that is designed to correspond to the cross-section 81 or121 of the plate shaped implant body 10. In other words, the plateshaped implant body 10 fits the guide channel 54, with a slighttolerance to allow a sliding movement of the implant in the guidechannel 54. The positioning body 11 has a mouth or muzzle 29 which isthe guide channel's 54 opening on the cartilage contact surface 50. Themouth 29 is in a position on the cartilage contact surface 50,corresponding to the site of the diseased cartilage in a joint. Theheight 31 of the guide channel 54 must be sufficiently long to givesupport to the tools used inside the guide body 13. The height 31 ispreferably higher than the thickness of the surrounding tissue. In thisway, the opening of the guide channel 54 is easy to access for thesurgeon. The height 31 of the guide channel 54 is between 1 and 10 cm,preferably 3-10 cm, and always sufficiently high to ensure stabilizationof the tools that are to be inserted into the guide channel 54.

The guide tool 12 is easy to place due to the precise fit of thepositioning body 11 on the cartilage surface. The guide tool 12 isdesigned to be inserted in as lesion which is as small as possible to beable to repair the specific cartilage damage. The height 31 of the guidechannel 54 is sufficiently high to be easily accessible for the surgeonduring surgery. In one embodiment, the top of the guide channel 54 isdesigned to project above the tissue surrounding the surgery cut whenthe guide tool is placed on the cartilage in a joint during surgery.

The size and shape of cartilage contact surface 50 of the guide tool 12is determined depending on the size, shape or spread of the damagedcartilage and thus on the cross section (for example 81) of the implantbody 10 and the guide channel 54, and also depending on the position ofthe cartilage area in a joint. The size, shape or spread of the surface50 is a consideration between the following aspects; minimize surgerylesion, maximize stability for guide tool 12, anatomic limitations onthe site of the injury. Not all cartilage surfaces in a joint can beused for placement of the guide tool. A large spread of the cartilagecontact surface 50 is to prefer to get good stability of the guide tool,however, a large surface area of the surface 50 may also lead to a largesurgical intervention which is undesired. Thus the size of the cartilagecontact surface 50 and of the positioning body 13 is determined by abalance between the desire to achieve good positioning stability andsmall surgical operations. Also, the cartilage contact surface 50 doesnot need not have a continuous, regular shape, but may have an irregularshape, as long as it gives adequate support and stable positioning ofthe guide tool 12. The cartilage contact surface may also consist ofthree separated points.

When designing the guide tool, the cartilage contact surface 50 can bedesigned to cover three points (see FIG. 4 a, 40, 42, 44 for an example)distributed over the cartilage surface of the joint where the implant isto be inserted. The points are chosen to give maximum support andpositional stability for the positioning body 11 and thus these points,either decided and identified by the surgeon or automatically identifiedby design software, serve the ground when designing the surface 50 ofthe guide tool 12. The cartilage contact surface 50 can also be formedsuch that it uses the curvature in the cartilage surface in a joint forstability. For example, in a knee joint, the condyles are separated fromeach other by a shallow depression, the posterior intercondyloid fossa,this curvature together with the medial epicondyle surface can be usedto give the cartilage contact surface 50 a stabile attachment to thecartilage surface in a knee joint. The cartilage contact surface doesnot need to be a continuous, regular surface but preferably has thethree points exemplified by 40, 42 and 44 for stability. Optionally thecartilage contacting surface 50 can be further stabilized by attachmentwith nails, rivets or similar attachment means to the bone surroundingthe cartilage in a joint (see FIG. 4 b). This additional attachment withrivets 48 or the like gives additional support and stability and alsogives the possibility to keep the cartilage contact surface as small aspossible. The position of the rivets may be predetermined and marked outon the surface 50 by premade drill holes 33.

The guide-tool 12 aids with exact precision removal of a volume ofcartilage and subchondral bone and the guide tool 12 also guides theplacement of the implant 10 in for example a knee. Placement of anexemplified embodiment of the guide-tool 12 on the cartilage surface ona knee can be seen in FIG. 4 a.

The guide body 13 comprises an orifice, see FIG. 11, at the foot of theguide body that leads from the guide channel into the open outside theguide body. The orifice 145 is designed to enable output of waste suchas cartilage tissue and bone chips from boring or reaming in thepreparation of the recess for the implant in the joint. The orifice ispreferably also designed to enable visual inspection into the implantsite during surgical operation.

The Cartilage Cutting Tool

The cartilage cutting tool is a tool which is used to cut the cartilagein the joint around the area of damaged cartilage to prepare for theinsertion of the implant. The cartilage cutting tool may for example bea punch 6 or a cartilage cut drill 105, as shown in FIGS. (2, 5 a-b, 9b, 10). It is used inside the guide channel 54 of the guide tool 12 andfits in the guide channel 54, with a slight tolerance to allow a slidingmovement of the cartilage cutting tool in the guide channel 54. Thecartilage cutting tool preferably cuts the cartilage so that the cutedges of the cartilage are sharp and smooth. These sharp and smoothedges are of great importance when the implant is placed into theprepared recess in the cartilage and bone. In one embodiment thecartilage cutting tool, in addition to cutting the cartilage, may alsocut/carve/drill the underlying bone. A hole in the cartilage which iscut (punched or drilled) with the cartilage cutting tool according tothe inventive concept ends up with a precise fit of the implant into theprepared cartilage since the cartilage cutting tool allows for an exact,precise cut. The recess in the cartilage and/or bone, made by thecartilage cutting tool always correspond to the chosen cross-section 81of the implant surface 15 in size and shape (see FIG. 8).

In one exemplifying embodiment of the inventive concept the cartilagecutting tool is a punch 6. The punch 6 is a solid body with a hollowshape or recess 5 in one end. The recess 5 has sharp edges 60. The punch6 is used to punch out and remove the damaged cartilage from the joint.The punch is to be placed inside the guide channel 54 of the guide tool12, with the recess pointing down onto the cartilage. A hammer is thenused to hammer the punch recess 5 through the cartilage. In this way thedamaged cartilage is removed by punching. The depth 59 of the recess 5on the punch 6 may be adjusted to the individual person's cartilagethickness. It is of great importance that the punch has sharp cuttingedges 60.

The punch 6 fits the inside of the guide channel 54, see FIG. 8, with aslight tolerance to allow a sliding movement of the punch in the guidechannel 54. The fit ensures the correct, desired placement of the punchon the cartilage surface and thus the precise removal of the damagedcartilage area. The punch preferably gives sharp precise edges of theremaining cartilage in the joint surrounding the removed cartilagepiece, which is of importance when placing the implant 10 in the joint.The contour of the cutting edge 60, i.e. the contour of the surface ofthe cutting edge 60 that is to face and cut the cartilage, is in oneembodiment designed to match the contour of the patient's cartilageand/or bone at the site of the joint where the punch is to cut. Thisfurther ensures that the cartilage will be properly and efficiently cut,giving sharp precise edges of the remaining cartilage as well asminimized damage to the underlying bone.

The length 56 of the punch 6 is in one embodiment longer than the height31 of the guide channel 54. The length 56 of the punch 6 is preferablybetween 4 and 12 cm.

The cross-sectional profile 83 or 123, and thus the circumferentialshape of the cutting edge 60, of the punch 6 corresponds to the chosencross-section 81 or 121 of the implant surface 15 in size and shape (seeFIG. 8 a-b). The cross-sectional profile 83 or 123 of the punch variesin different realizations of the inventive concept between 0.5 cm² and20 cm², between 0.5 cm² and 15 cm², between 0.5 cm² and 10 cm² orpreferably between about 1 cm² and 5 cm².

In one exemplifying embodiment of the inventive concept the cartilagecutting tool is a cartilage cut drill 105. The cartilage cut drill 105is used to cut the cartilage in the joint around the area of damagedcartilage to prepare for the insertion of the implant with a cut-drilltechnique.

The cartilage cut drill 105 is a drill, with a drill body 111 and withsharp cutting edges 108 and a center marker 106. The cartilage cut drill105 has a cross-sectional profile that is designed to correspond to theinner cross-sectional profile 122 of the guide channel 54 with atolerance enabling cartilage cut drill body 111 to slide within theguide channel 54. Also, the cross-sectional profile is designed tocorrespond to the cross-section of the implant.

The Reamer Guide

In one embodiment of the inventive concept the surgical kit comprises areamer guide 28 that is placed in the guide channel 54 before reamingthe recess in the bone (see FIG. 2 and FIG. 7 c-7 d, 8 a-8 b, 9 d). Thereamer guide 28 placed in the guide channel 54 protects the cartilagesurrounding the implant site while the reamer bit 4 is used inside theguide channel 54 of the guide tool 12.

The reamer guide 28, see FIG. 7, is a channel shaped structure with thinwalls designed to fit the inside of the guide channel 54, with a slighttolerance to allow a sliding movement of the reamer guide 28 in theguide channel 54. In other words, the cross sectional profile 85 of thereamer guide 28 fits the cross sectional profile 82 of the guide channel54 such that the reamer guide 28 may be used as a lining, lining theinsides of the guide channel 54 (see FIG. 8). The walls of the reamerguide 28 have a thickness of less than 1 mm. The reamer guide 28preferably has a height 66 that is at least the height achieved byadding the inner height 31 of the guide channel 54 with the height 59 ofthe recess 5 of the punch 6.

The Drill-Guide

In one embodiment of the inventive concept the surgical kit comprises adrill guide 8 (see FIG. 2, 6 a-6 b, 8 a-8 b, 9 c) that is used to directa drill for drilling a hole in the bone at the site of cartilage damage,for fastening of the extending post 23 of the implant 10 in the bonetissue. The drill guide 8 comprises a drill guide body and a guidechannel 7 passing through the drill guide body. The guide channel 7 isdesigned to receive and guide the drill during the surgical procedure.The drill guide 8 is designed to fit the inside of the guide channel 54,with a slight tolerance to allow a sliding movement of the drill guide 8in the guide channel 54, see FIG. 8 a-b. In other words, thecross-sectional profile (84, 124) of the drill guide body matches thecross-sectional profile of the guide channel 54 (see FIG. 8 a-b). Thefit ensures the correct, desired placement of the drill guide 8 on thecartilage surface and thus ensures the precise direction and placementof the drill hole in the bone.

The guide channel 7 is designed to be positioned in the drill guide bodysuch that the position corresponds to the desired position of the drillhole in the bone. The positioning of the guide channel 7 in the drillguide 8 is coordinated with the positioning of the extending post 23 onthe bone contacting surface 21 of the implant to ensure correctpositioning of the implant in the bone.

The length 62 of the drill guide 8 and thus the drill channel 7 islonger than the height 31 of the guide channel 54. The length ispreferably 4-12 cm.

The cartilage contacting surface 64 of the drill guide 8 corresponds tothe chosen implant surface 15 in size and shape. The surface 64 variesin different realizations of the inventive concept between 0.5 cm² and20 cm², between 0.5 cm² and 15 cm², between 0.5 cm² and 10 cm² orpreferably between about 1 cm² and 5 cm². In one embodiment thecartilage contacting surface 64 of the drill guide 8 is designed tomatch the contour of the patient's cartilage and/or bone at the site ofthe joint where the implant is to be inserted.

See FIG. 9 c for a demonstration of how the drill-guide 8 fits insidethe guide-channel 54 of the guide-tool 12.

Drill-Bit

The surgical kit of the present inventive concept may also comprise adrill-bit 2 see FIGS. 2 and 7 a. The drill-bit 2 may have an adjustabledepth gauge 1. The depth gauge 1 on the drill-bit 2 is supported by thetop 30 of the guide channel 54 and by using this support the depth ofthe drill hole can be controlled. The drill-bit 2 fits inside the drillchannel 7 in the drill-guide 8 to give a drill-hole in the bone with anexact position and depth and where the depth is depending on theplacement of the depth gauge 1 on the drill-bit 2, and also depending onthe height of the guide-channel 31.

Depth Adjustment Tool

The surgical kit of the present invention may also comprise a depthadjustment tool 2000, se FIG. 17 and FIG. 18. The depth adjustment tool2000 according to the present invention comprises a drill depth bit2012, a drill depth assembly holder 2010 and a drill depth spacer 2008.

The depth adjustment tool 2000 according to the present invention may beused together with the drill guide 8 and the drill bit 2 comprising adrill depth gauge 1, see FIG. 19A-B.

In FIG. 19A-B an example of usage of the depth adjustment tool 2000according to the present invention is shown.

Step 1 in FIG. 19A show the drill guide 8 inserted together with thedrill bit 2 inside the guide channel 54, of the guide tool 12. The drillbit 2 is inserted proximate to the underlying bone or cartilage.

In step 2 in FIG. 19A, the depth adjustment tool 2000 is placed onto thetop of the guide channel 54 comprising the drill guide 8 and secured onthe guide channel 54.

In step 3 in FIG. 19A, the drill depth gauge 1 of the depth adjustmenttool 2000 is placed proximate to the drill depth bit 2012 and thenattached to the drill-bit 2.

In step 4 in FIG. 19A the drill depth bit 2012, which determines theplacement of the drill depth gauge 1 on the drill bit 2, is removed andthen the drilling of the recess intended for the implant 10 or extendingpost 23 of the implant 10 may start.

The drill depth assembly holder 2010 holds the drill depth spacer 2008which comprises several removable spacers 2016 of 0.1 micrometer to 1 mmthickness.

In step 5 in FIG. 19B, if the drill depth need to be further adjusted,the lowest spacer may be removed which allows the drill bit 2 to drill adeeper recess in the bone, the additional depth is depending on thethickness of the spacer 2016 or spacers (for example 2016A and 2016B)which is removed. Several spacers 2016 may be removed if a deeper recessis needed see for example step 6 in FIG. 19B.

Reamer-Bit

The surgical kit of the present inventive concept may also comprise areamer-bit, see FIGS. 2 and 7 b. The reamer-bit 4 may have a depth gauge3. The reamer bit 4 is used together with the guide-tool 12 and possiblythe reamer guide 28. The reamer-bit 4 is used inside the guide channel54, removing bone tissue, aided by the guide channel 54 and possibly thereamer guide 28. The depth gauge 3 on the reamer-bit 4 is supported bythe top 30 of the guide channel 54 and by using this support the depthof the reamed bone recess can be controlled. The depth of the reamedrecess in the bone is depending on the placement of the depth gauge 3 onthe reamer-bit 4, and also depending on the height 31 of theguide-channel 54. The depth of the reamed surface is determineddepending on the injury and on the desired implants size.

Hammer Tool

The optional hammer tool 35 (see FIGS. 2 and 7 e-f, 9 f) consists of asolid body and is designed to fit the inside of the guide channel 54,with a slight tolerance to allow a sliding movement of the hammer tool35 in the guide channel 54, see FIG. 8. The hammer tool 35 is usedinside the guide channel 54 to hammer the implant in place. The heightof the hammer tool 68 is the same height 62 as of the drill guide 8.Once the hammer tool is hammered in the same level as the top of theguide channel, the hammering and thus the placement of the implant isfinished.

The invention claimed is:
 1. A method of manufacturing a surgical kitfor cartilage repair in an articulating surface of a joint, comprisingthe steps of: I. Receiving design parameters for a surgical kit in acomputer controlled manufacturing system, said design parameters for thesurgical kit representing a model for a medical implant and a guide toolfor implanting said implant; II. Manufacturing a medical implantdependent on design parameters for: a. the contour curvature for anarticulate surface of a substantially plate shaped implant body; b. across-section for an implant body; c. an edge height for an implantbody; d. a length and a cross-section profile for an extending postextending from a bone contacting surface of the implant; III.Manufacturing a guide tool for implanting said implant dependent ondesign parameters for: e. a cartilage contact surface of a positioningbody; f. a cross-section profile for a guide channel in a guide bodyextending from the positioning body, said guide channel passing throughsaid positioning body and said guide body, the cross-section profile forthe guide channel having a cross-sectional profile that corresponds tothe cross-section of the plate shaped implant body, wherein the plateshaped implant body fits the guide channel, with a slight tolerance toallow a sliding movement of the implant in the guide channel, and suchthat the guide channel is designed to have a muzzle on the cartilagecontact surface of the positioning body at a position corresponding tothe site of the diseased cartilage; g. a cross-section profile for aninsert tool having a cross-sectional profile that corresponds to thecross-sectional profile of the guide channel with a tolerance enablingthe insert tool to slide within the guide channel.
 2. The method ofclaim 1, further comprising manufacturing an insert tool provided in theform of a drill guide having a cross-sectional profile that correspondsto the cross-sectional profile of the guide channel with a toleranceenabling the drill guide to slide within the guide channel, and designparameters for position and dimension for a drill channel through thedrill guide for guiding a drill bit, the drill channel being placed in aposition that corresponds to the position of the extending post of themedical implant.
 3. The method of claim 2, further comprisingmanufacturing a drill bit dependent on design parameters for a drill bitdependent on design parameters for the extending post and such that across-sectional area for a drill bit is slightly smaller than thecross-sectional area for the extending post.
 4. The method of claim 1,wherein the design parameters for the drill channel comprises designparameters for a cross-sectional area that matches the cross-sectionalarea of the drill bit with a tolerance enabling the drill bit to slidewithin the drill channel.
 5. The method of claim 3, wherein the designparameters for the drill bit comprises generating dimensions andposition for a depth gauge on the drill bit for adjustment of the depthof drilling.
 6. The method of claim 1, further comprising manufacturingof an insert tool in the form of a reamer guide dependent on designparameters for a reamer guide with a cross-sectional profile that isslightly smaller than the cross-sectional profile of the guide channelwith a tolerance enabling the reamer guide to slide within the guidechannel.
 7. The method of claim 1, further comprising manufacturing aninsert tool in the form of a cartilage cutting tool design parametersfor a cartilage cutting tool with a cross-sectional profile that isdesigned to correspond to the cross-sectional profile of the guidechannel with a tolerance enabling the cartilage cutting tool to slidewithin the guide channel.
 8. The method of claim 7, wherein the designparameters for a cartilage cutting tool comprises design parameters fora cutting tool in the form of a punch having an end with a cuttingsurface, said end having a recess with a cross-sectional profile thatsubstantially corresponds to the cross-section of the plate shapedimplant body.
 9. The method of claim 7, wherein the design parametersfor a cartilage cutting tool comprises design parameters for a cuttingtool in the form of a cartilage cut drill having a cross-sectionalprofile that substantially corresponds to the cross-section of the plateshaped implant body.
 10. The method of claim 1, wherein the designparameters for the implant comprises design parameters for an implantbody of the implant being substantially flat, having a thickness ofapproximately 0.5-5 mm.
 11. The method of claim 1, wherein the designparameters for the cartilage contact surface of the positioning bodycomprises design parameters for a positioning body having threecontacting points spread out around the guide body, for contacting partsof the joint in order to provide stable positioning of the guide tool inthe joint.
 12. The method of claim 1, wherein the design parameters forthe guide channel defines the guide channel to have a height of 3-10 cm.13. The method of claim 1, wherein the design parameters for the guidechannel comprises design parameters for an orifice leading through theguide body at the foot of said guide body.
 14. The method of claim 1,further comprising manufacturing of an insert tool in the form of ahammer tool dependent on design parameters for a hammer tool with across-sectional profile that is designed to correspond to thecross-sectional profile of the guide channel with a tolerance enablingthe hammer tool to slide within the guide channel.
 15. The method formanufacturing according to claim 1, further comprising design andmanufacturing of a depth adjustment tool comprising a drill depth bitand a drill depth assembly holder and a drill depth spacer wherein thedepth adjustment tool is designed and manufactured to fit onto the topof the guide channel comprising the drill guide and also designed andmanufactured to be able to be secured on the guide channel.